Alzheimer's disease currently affects over 35 million people worldwide and the effects of the disease are devastating to patients as well as their families and caretakers. It is estimated that the global cost of Alzheimer's disease is $315 billion annually. While a great deal of progress has been made in understanding the biochemical basis for the disease and in developing compounds to slow its progression, this knowledge has yet to be translated into a treatment, cure, or even a reliable diagnostic technique.
One aspect of the neurochemistry that shows promise is the identification of iron as a biomarker for Alzheimer's disease. Over the past several years, researchers have worked on locating and characterizing unusual iron oxide particles that form in association with neurodegenerative diseases such as Alzheimer's disease, and it has been determined that magnetite and other iron oxides tend to form in brain tissue in association with such diseases. It is now believed by some that excess or unusual iron oxides, such as magnetite, may be formed early in the Alzheimer's disease process, possibly due to a malfunction of the normal iron storage protein, ferritin. If iron oxides associated with neurodegeneration could be detected early in the progression of the disease, new treatments could be developed and existing treatments could be initiated earlier. Early treatment is of particular importance in the case of Alzheimer's disease because much of the tissue in critical areas of the brain may already be irreparably damaged by the time symptoms appear.
Synchrotron radiation has been used to locate and characterize iron in post-mortem brain tissue. However, such radiation cannot be applied to living patients. Although several attempts have been made to identify iron using magnetic resonance imaging (MRI), such attempts have been largely unsuccessful. Many of these attempts have been focused on regional changes in MRI signals due to regional iron accumulation. Such attempts have for the most part not resulted in the detection of clinically relevant, statistically significant differences between signals from control and diseased tissue. One reason for this may be that regional changes are not sufficiently correlated with the disease process. In addition, the signals used to identify iron concentration may be confounded by other tissue effects that produce changes similar to those of iron, such as changes in tissue magnetic susceptibility or proton concentration. Furthermore, the averaging of MRI signals at a large spatial scale that is typically performed in MRI may obscure the signatures of iron concentrated on small spatial scales.
From the above discussion, it can be appreciated that it would be desirable to have an alternative system and method for detecting the presence of iron within tissue, such as brain tissue.